Structured population data were available for 3 of 3 supporting studies. 2 studies described participants with type 2 diabetes. 2 studies described adult participants.

1 supporting study does not have a displayable topic-matched quantitative effect.

3 of 3 studies with duration data have follow-up of 12 weeks or less.

Placebo Group

Core clinician-reference fields are available or not applicable.

Patients received two tablets of 250 mg melatonin once a day for 8 weeks.

Melatonin Group

The intervention group used two tablets of melatonin (250 mg/day, 1 h before bedtime) containing 3 mg net melatonin for 8 weeks.

Patients received two tablets of placebo once a day for 8 weeks.

The control group used two tablets of placebo (250 mg/day, 1 h before bedtime) containing magnesium stearate, cellulose, silicon dioxide, and starch.

Melatonin improves glycemic control in type 2 diabetes patients

Patients receiving 6 mg of melatonin nightly.

After the collection of the 1st blood samples, bedtime administration of 6 mg melatonin (NatureMade®, USA) or placebo with identical appearance was initiated.

Patients receiving a placebo that contained cellulose instead of melatonin.

The placebo contained cellulose instead of melatonin and both the tablets had the same size, shape, color, odor and package.

Melatonin shows little effect on glycemic control in type 2 diabetes

Available source content was suppressed because validation identified a conflict.

Participants received synthetic melatonin only on days off and between shifts for 12 weeks.

The melatonin group (12 weeks) used synthetic melatonin (3 mg) only on days off and between shifts.

Participants were instructed to take a placebo pill identical in appearance to the melatonin pill for 12 weeks.

The placebo group (12 weeks) was instructed to take a placebo, also on days off and between shifts.

Authoritative quality diagnostic: invalid or missing unit.

Authoritative quality diagnostic: invalid or missing value.

Melatonin shows no effect on diabetes risk markers in night workers

Structured population data were available for 3 of 3 supporting studies. 1 study described participants with type 2 diabetes. 3 studies described adult participants.

Structured population data were available for 3 of 3 supporting studies. 2 studies described participants with type 2 diabetes. 3 studies described adult participants.

1 study contains conflicting p-value and significance fields; those significance claims are suppressed.

Structured population data were available for 4 of 4 supporting studies. 3 studies described participants with type 2 diabetes. 4 studies described adult participants.

Upstream consistency scoring indicates mixed findings across the evidence.

Evidence uses heterogeneous comparison contexts: active_comparator, usual_care.

Structured population data were available for 8 of 8 supporting studies. 4 studies described participants with type 2 diabetes. 8 studies described adult participants.

1 relevant study has unresolved authoritative design evidence and does not contribute to design-specific or RoB-specific claims.

Evidence uses heterogeneous comparison contexts: baseline_within_group, unknown_unresolved, usual_care.

2 supporting studies have high, serious, critical, unclear, or unavailable risk-of-bias information.

Evidence uses heterogeneous comparison contexts: baseline_within_group, usual_care.

2 supporting studies do not have a displayable topic-matched quantitative effect.

Evidence uses heterogeneous comparison contexts: active_comparator, unknown_unresolved.

3 supporting studies have high, serious, critical, unclear, or unavailable risk-of-bias information.

Structured population data were available for 4 of 4 supporting studies. 4 studies described participants with type 2 diabetes. 4 studies described adult participants.

Structured population data were available for 5 of 5 supporting studies. Diabetes type was heterogeneous: 2 studies with type 1 diabetes, 1 studies with type 2 diabetes. Age groups were heterogeneous: 2 studies with adult participants, 1 studies with youth participants.

2 relevant studies have unresolved authoritative design evidence and do not contribute to design-specific or RoB-specific claims.

Evidence uses heterogeneous comparison contexts: baseline_within_group, other, usual_care.

4 of 5 studies with duration data have follow-up of 12 weeks or less.

Structured population data were available for 10 of 11 supporting studies. Diabetes type was heterogeneous: 5 studies with type 2 diabetes, 2 studies with type 1 diabetes. 8 studies described adult participants.

3 relevant studies have unresolved authoritative design evidence and do not contribute to design-specific or RoB-specific claims.

3 supporting studies do not have a displayable topic-matched quantitative effect.

Evidence uses heterogeneous comparison contexts: active_comparator, baseline_within_group, placebo, unknown_unresolved, usual_care.

1 supporting study lacks usable structured population information.

4 supporting studies have high, serious, critical, unclear, or unavailable risk-of-bias information.

Structured population data were available for 8 of 8 supporting studies. 7 studies described participants with type 2 diabetes. 7 studies described adult participants.

Evidence uses heterogeneous comparison contexts: active_comparator, baseline_within_group, placebo.

1 supporting study has high, serious, critical, unclear, or unavailable risk-of-bias information.

Structured population data were available for 4 of 4 supporting studies. 4 studies described participants with type 1 diabetes. 2 studies described adult participants.

Structured population data were available for 8 of 8 supporting studies. 6 studies described participants with type 2 diabetes. 7 studies described adult participants.

Evidence uses heterogeneous comparison contexts: active_comparator, unknown_unresolved, usual_care.

Structured population data were available for 8 of 8 supporting studies. Diabetes type was heterogeneous: 4 studies with type 2 diabetes, 1 studies with type 1 diabetes. Age groups were heterogeneous: 4 studies with adult participants, 1 studies with youth participants.

Evidence uses heterogeneous comparison contexts: active_comparator, placebo, usual_care.

5 of 8 studies with duration data have follow-up of 12 weeks or less.

Structured population data were available for 3 of 3 supporting studies. 3 studies described participants with type 2 diabetes. 3 studies described adult participants.

Evidence uses heterogeneous comparison contexts: active_comparator, placebo.

Evidence uses heterogeneous comparison contexts: active_comparator, baseline_within_group.

Structured population data were available for 3 of 3 supporting studies. Diabetes type was heterogeneous: 1 studies with type 1 diabetes, 1 studies with type 2 diabetes. 2 studies described adult participants.

Structured population data were available for 13 of 13 supporting studies. 11 studies described participants with type 2 diabetes. 12 studies described adult participants.

4 relevant studies have unresolved authoritative design evidence and do not contribute to design-specific or RoB-specific claims.

Evidence uses heterogeneous comparison contexts: active_comparator, baseline_within_group, usual_care.

Evidence uses heterogeneous comparison contexts: unknown_unresolved, usual_care.

Structured population data were available for 3 of 3 supporting studies. Diabetes type was heterogeneous: 2 studies with type 2 diabetes, 1 studies with type 1 diabetes. Age groups were heterogeneous: 2 studies with adult participants, 1 studies with youth participants.

Structured population data were available for 12 of 12 supporting studies. Diabetes type was heterogeneous: 9 studies with type 2 diabetes, 1 studies with type 1 diabetes. 12 studies described adult participants.

9 supporting studies have high, serious, critical, unclear, or unavailable risk-of-bias information.

Structured population data were available for 5 of 5 supporting studies. 5 studies described participants with type 2 diabetes. 4 studies described adult participants.

Structured population data were available for 2 of 3 supporting studies. 2 studies described participants with type 2 diabetes. 2 studies described adult participants.

Evidence uses heterogeneous comparison contexts: active_comparator, placebo, unknown_unresolved.

Structured population data were available for 10 of 10 supporting studies. Diabetes type was heterogeneous: 8 studies with type 2 diabetes, 2 studies with type 1 diabetes. Age groups were heterogeneous: 8 studies with adult participants, 1 studies with youth participants.

Evidence uses heterogeneous comparison contexts: active_comparator, other, usual_care.

3 studies contain conflicting p-value and significance fields; those significance claims are suppressed.

Structured population data were available for 4 of 4 supporting studies. 2 studies described participants with type 2 diabetes. 4 studies described adult participants.

Evidence uses heterogeneous comparison contexts: other, usual_care.

2 of 4 studies with duration data have follow-up of 12 weeks or less.

Structured population data were available for 4 of 4 supporting studies. Diabetes type was heterogeneous: 2 studies with type 2 diabetes, 1 studies with type 1 diabetes. 4 studies described adult participants.

Structured population data were available for 5 of 5 supporting studies. 5 studies described participants with type 2 diabetes. 5 studies described adult participants.

Structured population data were available for 11 of 11 supporting studies. 10 studies described participants with type 2 diabetes. 11 studies described adult participants.

Structured population data were available for 6 of 6 supporting studies. 6 studies described participants with type 2 diabetes. 6 studies described adult participants.

Evidence uses heterogeneous comparison contexts: active_comparator, baseline_within_group, unknown_unresolved, usual_care.

Structured population data were available for 7 of 7 supporting studies. Diabetes type was heterogeneous: 2 studies with type 2 diabetes, 1 studies with type 1 diabetes. 5 studies described adult participants.

Structured population data were available for 5 of 5 supporting studies. 3 studies described participants with type 2 diabetes. 4 studies described adult participants.

Structured population data were available for 5 of 5 supporting studies. Diabetes type was heterogeneous: 4 studies with type 2 diabetes, 1 studies with type 1 diabetes. 3 studies described adult participants.

Evidence uses heterogeneous comparison contexts: baseline_within_group, placebo, usual_care.

Melatonin × HbA1c

Available supporting studies

Melatonin improves glycemic control in type 2 diabetes patients

Melatonin shows little effect on glycemic control in type 2 diabetes

Melatonin shows no effect on diabetes risk markers in night workers